CN110027178B

CN110027178B - Molding system including mold stack having a clean configuration and a closure height adjustment mechanism

Info

Publication number: CN110027178B
Application number: CN201910169367.9A
Authority: CN
Inventors: 斯文·克莫赫; 拉尔夫·瓦尔特·菲施; 德里克·罗伯逊·麦克里迪; 雷纳托·帕帕; 马克斯菲尔德·保罗·布拉德肖
Original assignee: Husky Injection Molding Systems Ltd
Current assignee: Husky Injection Molding Systems Ltd
Priority date: 2015-03-20
Filing date: 2016-02-24
Publication date: 2021-12-24
Anticipated expiration: 2036-02-24
Also published as: CA2977296A1; EP3800030B1; US20180050476A1; JP6974535B2; CN110027178A; CN107249849B; EP3800030A1; CA2977296C; CA3055639C; CN107249849A; JP6679627B2; US20220347902A1; EP3549743B1; EP3271131B1; EP3271131A4; CA3055639A1; US11826936B2; US11420369B2; EP3549743A1; WO2016149800A1

Abstract

In one aspect, a mold stack may include two adjacent components, one at least partially defining a vent adjustable between a molding configuration and a cleaning configuration. The joints of the components are adjustable between a molding configuration in which the mating faces contact one another to define a parting line, and a cleaning configuration in which the mating faces are separated to form a mold cavity extension therebetween and an auxiliary melt barrier prevents uncontrolled flash from the extension. In another aspect, a closure height adjustment mechanism may comprise: a mold part movable along an operating axis of the mold; a stop member movable relative to the mold component along the axis, having first and second stops for providing first and second gaps on the front and back sides of the mold component, respectively, when the stop member is deployed; and a spacer for selectively deploying the stop member.

Description

Molding system including mold stack having a clean configuration and a closure height adjustment mechanism

Technical Field

The present invention relates to molding systems and molds, and in particular, to injection molds including a mold stack having a clean configuration and/or a closed height adjustment mechanism.

Background

A molding system, such as an injection molding system, forms a molded article from a molding material. The molding material may be a plastic or resin material, such as polyethylene terephthalate (PET). The molded article may be a container or container precursor, such as a preform that can be subsequently blown into a beverage container (e.g., a plastic bottle).

An injection molding system may heat a molding material, such as PET, to a homogeneous molten state, where the molding material may be referred to as a "melt. The melt may be injected under pressure into a mold cavity defined by a collection of parts called a "mold stack". The mold stack typically includes, among other components, a female cavity piece and a male core piece attached to a cavity plate and a core plate, respectively. The mold cavity defined by the mold stack may have a shape that substantially corresponds to the final cold state shape of the article to be molded.

During injection of the melt, a clamping force is applied to the cavity plate and the core plate that is sufficient to hold the cavity plate and the core plate together despite the opposing forces of the pressurized melt within the mold cavity. Once the mold cavity is filled with melt, the molded article is typically allowed to cool and harden within the mold cavity for a short period of time. Cooling causes the molded articles to shrink within the mold cavities so that the molded articles can remain associated with the core plate when the cavity and core plates are pushed apart. The molding system may use various types of demolding structures to assist in removing the molded articles from the core pieces. Examples of the release structure include a release plate and a release pin.

Molded articles such as preforms may include a neck portion (or "neck finish") in relief having various features. The neck features may include one or more of the following: threads for receiving and retaining a closure assembly (e.g., a bottle cap); a tamper-evident assembly configured to cooperate with the closure assembly to indicate whether the end product (e.g., a beverage container filled with a beverage) has been tampered with; and a support rail that cooperates with a component of the molding system. These features of the embossment make it difficult or impossible to remove the neck from the mold cavity defined by the one-piece female cavity piece. To this end, the neck portion is typically defined by a split mold insert (also referred to as a neck ring) designed to be laterally split into two or more parts/halves to release the neck portion of the cooled molded article for axial ejection from the core piece.

At the beginning of an injection molding cycle, the mold cavity is empty, i.e., filled with air. As the melt is injected, the melt gradually replaces the air in the mold cavity. Air is typically vented from the mold cavity through vent holes defined between the mold stack components at or near the ends of the melt flow path within the mold cavity. The vent holes may be sized to allow the passage of gas (typically air) but not the passage of melt therethrough. The size of the vent may be set according to the type and/or viscosity of the melt to be used. For example, where the molding material is PET, the vent may include a gap that is about 30 to 40 microns wide. Venting may improve the quality of the molded article by reducing or eliminating the risk of trapped air within the mold cavity, which may otherwise cause defects in the molded article.

When an injection molding system is operated over many molding cycles, residue can accumulate on the vent surfaces. The residue may for example consist of material dust, contaminants or other particles. This excessive accumulation of residue may prevent proper or complete evacuation of air from the mold cavity, which may compromise the quality of the molded article.

Disclosure of Invention

According to one aspect of the present invention, there is provided a mold stack comprising: two adjacent mold stack components for jointly defining at least a portion of a mold cavity; a vent at least partially defined by one of the mold stack components, the vent adjustable between: a molding configuration wherein the vent is configured to vent gas from the mold cavity while preventing passage of any substantial amount of melt therethrough; and a cleaning configuration, wherein the vent is configured to receive melt from the mold cavity to clean the vent; and a joint defined between two corresponding mating faces of the two mold stack components, the mating faces being adjustable between: a molding configuration in which the mating faces contact one another to define a parting line of the mold cavity; and a cleaning configuration, wherein the mating faces are separated to create a space between the mating faces that serves as an extension of the mold cavity, and wherein the junction further defines an auxiliary melt barrier for preventing uncontrolled flash from the extension.

In some embodiments, the auxiliary melt barrier comprises an auxiliary vent configured to vent gas from the extension of the mold cavity while preventing melt from passing through the extension of the mold cavity.

In some embodiments, the engagement portion comprises a tongue and groove connection.

In some embodiments, the auxiliary vent is located between the tongue and groove of the tongue and groove connection.

In some embodiments, the auxiliary vent is substantially parallel to an axis of operation of the mold stack.

In some embodiments, the two adjacent mold stack components are a split mold insert and a cavity insert.

In some embodiments, the groove is an annular groove in the end of the cavity insert.

In some embodiments, the split mold insert has a tapered male portion and the tongue is an annular tongue at a distal end of the tapered male portion.

According to another aspect of the invention, a method of cleaning a vent in a mold stack is disclosed, the method comprising: adjusting two mold stack components of a mold stack from: a molding configuration in which the two mold stack components jointly define at least a portion of a mold cavity, in which a vent at least partially defined by one of the mold stack components is configured to vent gas from the mold cavity while preventing passage of any substantial amount of melt therethrough, and in which two respective mating faces of the two mold stack components contact one another at a junction of the mold stack components to define a parting line of the mold cavity, to: a cleaning configuration wherein the vent is sized to receive melt and wherein the mating faces are separated to create a space between the mating faces that serves as a mold cavity extension and wherein the interface defines an auxiliary melt barrier; and injecting melt into the mold cavity, the injected melt entering the vent and entering the mold cavity extension, but being prevented from flashing beyond the mold cavity extension by the auxiliary melt barrier.

In some embodiments, the two adjacent mold stack components are a split mold insert having a tapered male portion and a cavity insert at least partially defining a tapered female seat, and the adjusting comprises partially withdrawing the tapered male portion from the tapered female seat.

According to another aspect of the present invention, there is disclosed a mechanism for adjusting a closing height of a mold, comprising: a mold member movable along an operating axis of the mold; a stop member movable relative to the mold component along the operating axis of the mold, the stop member having a first stop for providing a first gap at a front side of the mold component when the stop member is in a deployed position, the stop member also having a second stop for providing a second gap at a back side of the mold component when the stop member is in the deployed position; and a spacer movable between an inboard position aligned with the stop member and an outboard position misaligned with the stop member, the spacer for selectively blocking and thereby deploying the stop member to the deployed position.

In some embodiments, the first stop is defined by a front portion of the stop member and the second stop is defined by a rear portion of the stop member.

In some embodiments, the mold component is a first mold component, the front portion of the stop member extends from a head end of the stop member to and includes the first stop, and the front portion of the stop member is receivable within an opening by a thickness of a second mold component adjacent the first mold component within the mold.

In some embodiments, a length of a front portion of the stop member exceeds the thickness of the second mold component.

In some embodiments, the first mold member is a stripper plate and the second mold member is a core plate.

In some embodiments, the rear portion of the stop member extends between a trailing end of the stop member and the first stop, and the rear portion is slidably receivable within a bore through a thickness of the mold component.

In some embodiments, wherein the rear portion of the stop member comprises one or more circumferential grooves, each of the circumferential grooves for retaining an O-ring.

In some embodiments, the length of the rear portion of the stop member exceeds the thickness of the mold component.

In some embodiments, the first stop includes a protrusion protruding from the stop member.

In some embodiments, the protrusion comprises a radial flange.

In some embodiments, the second stop comprises a trailing end of the stop member.

In some embodiments, the trailing end of the stop member is configured to engage an adjacent mold component to provide the second gap on the back side of the mold component.

In some embodiments, the adjacent mold parts are tonnage blocks or cavity plates.

In some embodiments, the mechanism further comprises a retaining mechanism for retaining the stop member with the mold component such that the stop member has a limited range of play relative to the mold component along the operational axis of the mold.

In some embodiments, the mechanism includes a retaining pin attached to the mold component, the retaining pin and the mold component jointly surrounding at least a portion of the radial flange so as to define the limited range of play.

In some embodiments, the spacer vacates space for receiving a head end of the stop member when the stop member is in the stowed position when the spacer is in the outboard position.

In some embodiments, the spacer is reciprocally movable in a direction orthogonal to an operational axis of the mold.

According to another aspect of the present invention, there is disclosed a method of increasing the closure height of a mold, comprising: opening the mold along an operational axis of the mold; moving a spacer from an outboard position out of alignment with a stop member of the mold to an inboard position in alignment with the stop member of the mold; providing relative movement between the stop member and the spacer along the operational axis of the mold until the spacer blocks the stop member and thereby deploys the stop member to a deployed position; providing relative movement between the mould part and the deployed stop member until a first stop of the deployed stop member engages the mould part to provide a first gap on a front side of the mould part whereupon a second stop of the stop member is arranged to provide a second gap on a back side of the mould part; and closing the mold along the operational axis of the mold.

In some embodiments, the method further comprises providing relative motion between the stop member and the spacer until the stop member clears the spacer before moving the spacer from the lateral position to the medial position.

In some embodiments, the stop member is retained with the mold component by a retaining mechanism that provides a degree of play to the retained stop member relative to the mold component along the operational axis of the mold, and providing relative motion between the stop member and the spacer includes moving the mold component and the retained stop member toward the spacer.

In some embodiments, providing relative motion between the mold component and the deployed stop member comprises moving the mold component toward the spacer until a first stop of the deployed stop member engages the mold component.

According to another aspect of the present invention, there is disclosed a mold stack defining a mold cavity for molding a preform, the mold stack comprising: a lock ring defining a tapered concave seat; a split mold insert defining a molding surface of the mold cavity for molding a neck finish portion of the preform, the split mold insert having a split tapered male portion configured to mate with the tapered female seat of the lock ring to align and hold closed the split mold insert, the split mold insert further defining a recess extending coaxially through the split tapered male portion; a core ring defining a molding surface of the mold cavity for molding at least a portion of a top sealing surface of the preform, the core ring configured to be received within the recess defined in the split mold insert; and a vent for evacuating air from the mold cavity, the vent comprising: a primary vent; and a secondary vent, wherein the primary vent and the secondary vent are each defined between the split mold insert and the core ring.

In some embodiments, the primary vent is defined in part by a recessed face of the recess in the split mold insert.

In some embodiments, the secondary vent comprises a gap between the split mold insert and the core ring, the gap being substantially parallel to an axis of operation of the mold stack.

In some embodiments, the primary vent comprises a gap between the split mold insert and the core ring, the gap being substantially orthogonal to an axis of operation of the mold stack.

Other features will become apparent from the following description taken in conjunction with the accompanying drawings.

Drawings

In the accompanying drawings which illustrate non-limiting exemplary embodiments:

FIG. 1 is a cross-sectional view of a portion of a mold showing a single mold stack in a standard molding configuration;

FIG. 2 is a perspective view of a molded article that may be molded by the mold of FIG. 1 in a standard molding configuration;

FIG. 3 is a close-up view of a portion of the cross-sectional view of FIG. 1 with the core insert element removed for clarity;

FIG. 4 is a perspective view of a tapered female seat formed by a subcomponent of the mold of FIG. 1;

FIGS. 5 and 6 are perspective and plan views, respectively, of a split mold insert part of the mold of FIG. 1 in a standard molding configuration;

FIG. 7 is a perspective view of the split mold insert of FIGS. 5 and 6 separated into its two halves with their corresponding mating faces visible;

FIG. 8 is a close-up view of a portion of the cross-sectional view of FIG. 3;

FIG. 9 is a cross-sectional view of the same portion of the mold as shown in FIG. 1, but with the mold stack in a residue cleaning configuration;

FIG. 10 is a close-up view of a portion of the cross-sectional view of FIG. 9 with the core insert element removed for clarity;

FIGS. 11 and 12 are close-up views of portions of the cross-sectional view of FIG. 10;

fig. 13 and 14 are perspective and plan views, respectively, of the split mold insert part of fig. 5 and 6 in a residue cleaning configuration;

FIG. 14A is a perspective view of a molded article that may be molded by the mold of FIG. 9 in a residue cleaning configuration;

FIG. 15 is a cross-sectional elevation view of a portion of another mold embodiment, showing a single mold stack in a molding configuration;

FIG. 16 is a close-up view of a portion of the cross-sectional view of FIG. 15 with the core insert element removed for clarity;

FIGS. 17 and 18 are perspective and plan views, respectively, of the split mold insert of the mold of FIG. 15 in a molded configuration;

FIG. 18A is a perspective view of the split mold insert of FIGS. 17 and 18 separated into its two halves with their corresponding mating faces visible;

FIG. 18B is a close-up view of a portion of the cross-sectional view of FIG. 16;

FIG. 19 is a cross-sectional elevation view of the same portion of the mold as in FIG. 15, but with the mold stack in a residue cleaning configuration;

FIG. 20 is a close-up view of a portion of the cross-sectional view of FIG. 19 with the core insert element removed for clarity;

FIGS. 21 and 22 are perspective and elevation views, respectively, of the split mold insert of FIGS. 17 and 18 in a residue cleaning configuration;

FIG. 23 is a close-up view of a portion of the cross-sectional view of FIG. 20;

FIG. 24 is a side view of the mold with the closure height adjustment mechanism in a standard molding configuration;

FIGS. 25 and 26 are rear and front perspective views, respectively, of a cavity plate assembly of the mold of FIG. 24;

FIGS. 27 and 28 are rear and front perspective views, respectively, of a stripper plate assembly of the mold of FIG. 24;

FIG. 29 is a perspective view of a stop member forming part of the stripper plate assembly of FIGS. 27 and 28;

FIGS. 30 and 31 are rear and front perspective views, respectively, of a core plate assembly of the mold of FIG. 24;

FIGS. 32 and 33 are rear and front perspective views, respectively, of the spacer assembly of the mold of FIG. 24;

FIG. 34 is an exploded view of a portion of the mold of FIG. 24 showing a portion of the mold's closure height adjustment mechanism;

FIG. 35 is a schematic cross-sectional view of a portion of the closure height adjustment mechanism of the mold of FIG. 24 with the mold in a standard molding configuration;

FIG. 36 shows the mold of FIG. 24 performing a first operation of increasing the mold closing height;

FIG. 37 is a schematic cross-sectional view of a portion of the closure height adjustment mechanism of the mold of FIG. 36, which performs a first operation of increasing the closure height of the mold;

FIG. 38 shows the mold of FIG. 24 performing a second operation that increases the closed height of the mold;

FIG. 39 is a schematic cross-sectional view of a portion of the closure height adjustment mechanism of the mold of FIG. 38 performing a second operation that increases the closure height of the mold;

FIG. 40 shows the mold of FIG. 24 performing a third operation that increases the closed height of the mold;

FIG. 41 is a rear perspective view of the spacer assembly of the mold of FIG. 24 performing a third operation that increases the mold closing height;

FIG. 42 is a schematic cross-sectional view of a portion of the closure height adjustment mechanism of the mold of FIG. 40, which performs a third operation that increases the mold closure height;

FIG. 43 shows the mold of FIG. 24 performing a fourth operation that increases the mold closing height;

FIG. 44 is a schematic cross-sectional view of a portion of the closure height adjustment mechanism of the mold of FIG. 43, which performs a fourth operation that increases the mold closure height;

FIG. 45 is a schematic cross-sectional view of a portion of the closure height adjustment mechanism of the mold of FIG. 35, which performs a fifth operation of increasing the closure height of the mold; and

fig. 46 is a flowchart illustrating an operation for increasing the closing height of the mold of fig. 24.

Detailed Description

For the system components in the figures, in the following description, the use of the terms "top," "bottom," "right," "left," "rear," "front," "horizontal," "vertical," "front," and "rear" should not be construed as necessarily implying a particular orientation of the components during use.

Referring to fig. 1, a cross-sectional elevation view of a portion of a mold 100 is shown. The example mold 100 produces a molded article, which in this example is a preform 101 shown in fig. 2. The portion of the mold 100 shown in fig. 1 is a longitudinal cross-section of a single mold stack 103 used to make a single preform 101. It should be understood that the mold stack 103 may be one of many similar mold stacks (not shown) within the mold 100 that may co-mold many preforms in a single batch during a single injection molding cycle. For simplicity, mold 100 may include other components omitted from FIG. 1.

The mold stack 103 of FIG. 1 is in a production or molding configuration, i.e., a configuration suitable for receiving melt into the mold cavity 105 and forming the preform 101 shown in FIG. 2. It should be understood that the mold stack 103 has other configurations as well, including a vent cleaning configuration (also referred to as a "residue cleaning configuration" or simply a "cleaning configuration") as will be described below.

The exemplary mold 100 of fig. 1 includes a pair of mold halves that are relatively movable along an operational axis a of the mold. The first mold half includes a cavity plate assembly 102. The second mold half includes a core plate assembly 104 and a stripper plate assembly 125 movable along and relative to the operating axis a.

Cavity plate assembly 102 includes cavity insert 106 (cavity form), gate insert 107, cavity flange 109, and cavity plate 108. Cavity flange 109 retains cavity insert 106 and gate insert 107 within bore 117 in cavity plate 108. The cavity insert 106 defines the outer shape of the body 113 (fig. 2) of the preform 101 to be molded. The gate insert 107 defines the outer shape of the closed end 115 (fig. 2) of the preform 101 to be molded and defines a gate (orifice) through which molten molding material is injected into the mold cavity. For clarity, the

parts

106 and 107 are referred to as "inserts" because they are designed as modular parts for insertion into the bore 117 to facilitate mold manufacture and repair. In alternative embodiments, cavity piece 106 and gate insert 107 may form a portion of plate 108 and/or may comprise a single component.

Core plate assembly 104 includes a core insert 110 (in the form of a core piece) that defines an inner surface of preform 101 to be molded. Core plate assembly 104 also includes a lock ring 111, lock ring 111 being configured to define a portion of a top sealing surface 121 of preform 101 (fig. 2). The lock ring is also configured to retain the core insert 110 on the core plate 112.

Stripper plate assembly 125 includes a stripper plate 120, slide bars 122, 123 slidably coupled to the stripper plate, and a split mold insert 114 for defining a neck finish 119 of preform 101 (fig. 2). The split mold insert 114 comprises a pair of complementary split mold insert halves 116, 118 attached to slide

bars

122, 123, respectively. The slide bars 122, 123 are operable to laterally (vertically in fig. 1) separate split mold insert halves 116, 118 during release of the molded articles.

As shown in fig. 1, the mold 100 has an operating axis a. The operating axis a may be considered to be the axis along which the major components of the mold 100 (e.g., the cavity plate assembly 102, the core plate assembly 104, and the stripper plate assembly 125) move during operation of the mold throughout an injection molding cycle. For example, core plate assembly 104 and stripper plate assembly 125 may be moved relative to cavity plate assembly 102 along an operational axis a to open the mold for ejecting preform 101 or close the mold in preparation for a subsequent injection molding cycle. Similarly, the stripper plate assembly 125 is movable relative to each of the cavity plate assembly 102 and the core plate assembly 104 along the operational axis a. Moving stripper plate assembly 125 away from core plate assembly 104, wherein the split mold insert halves support supports 116, 118 of neck finish 119 of preform 101, can facilitate stripping of preform 101 from core insert 110 during normal molding operations. In this embodiment, the cavity plate assembly 102 is stationary.

The operational axis a of the die 100 may alternatively be referred to as the operational axis of the die. As used herein, the term "mold" refers to cavity plate assembly 102, core plate assembly 104, and stripper plate assembly 125, while the term "molding system" refers not only to those components, but also to other components, such as mold clamps and injection units (not shown in fig. 1). The operational axis a of the mold 100 is parallel to the longitudinal operational axis of the mold stack 103 (i.e., the axis along which the cavity and core pieces of the mold stack open and close) and thus may also be considered the operational axis of the mold stack 103.

The mold stack 103 shown in FIG. 1 may be referred to as a cavity lock mold stack. The term "cavity lock" reflects a design in which the split mold insert halves 116, 118 are "locked" together laterally (vertically in fig. 1) due to being placed tightly within the seats defined by the cavity portions of the mold stack 103, as clamping pressure is applied to the mold stack 103 in the axial direction. This relationship is shown in more detail in fig. 3.

Referring to FIG. 3, a close-up cross-sectional elevation view of a portion of the mold stack 103 is depicted. Fig. 3 illustrates the interaction between the lock ring 111, split mold insert 114, cavity flange 109, and cavity insert 106 when the example cavity-lock mold stack 103 is in a molding configuration. It should be noted that the core insert 110 is omitted for clarity as shown in fig. 3.

As shown, the cavity flange 109 and the cavity insert 106 combine to define a tapered concave seat 130 having a generally frustoconical shape. Adjacent split mold inserts 114 have a tapered male portion 132, the male portion 132 having a complementary shape (i.e., generally frustoconical), which allows the tapered male portion 132 to be closely received within the tapered female seat 130 when the split mold insert 114 and cavity insert 106 are in the mated molded configuration of fig. 3. The shape of these features can best be seen in fig. 4 and 5, which provide a perspective view of the tapered female seat 130 and a perspective view of the tapered male portion 132, respectively.

Referring to FIG. 4, it can be seen that the cavity insert 106 and cavity flange 109 shown isolated from the remaining components of the mold stack 103 (the latter shown in phantom) combine to define the tapered female seat portion 130 of the present embodiment. The cavity flange 109 has a circular central aperture 128 defined by an inwardly tapered wall 129. The wall 129 terminates at a parting line 131 formed between the cavity flange 109 and the cavity insert 106. The cavity insert 106 defines an annular groove 135 at the deepest location of the conical concave seat 130. In this embodiment, an annular groove 135 is formed between the central annular lip 133 and a peripheral wall 137, the peripheral wall 137 having a taper matching the taper of the wall 129 of the cavity flange 109.

Turning to FIG. 5, in conjunction with FIG. 6, a split mold insert 114 isolated from other mold stack components is shown in perspective and elevation views, respectively. In each of fig. 5 and 6, split mold insert 114 is shown in a molded configuration with its

halves

116, 118 mated. The tapered male portion 132 of the insert 114 splits along a split line 143, a first half 136 of the male portion 132 forms part of the split mold insert half 116, and a second half 138 of the male portion 132 forms part of the split mold insert half 118.

Split mold insert halves 116, 118 jointly define a vent 145 therebetween (i.e., vent 145 is defined by split mold insert half 116 and by split mold insert half 118). The vent 145 includes a primary vent 149 (horizontally oriented in fig. 6) in fluid communication with a secondary vent 147 (vertically oriented in fig. 6). Each of the primary and secondary vents of the present embodiment includes a gap between split mold insert halves 116, 118. When the split mold insert 114 is in the molded configuration as shown in fig. 5 and 6, the vent 145 is configured to vent air from the mold cavity 105 while preventing any substantial amount of melt from passing through. This may be achieved by appropriate sizing of the gap consisting essentially of each of the primary and secondary vent holes 149, 147 (e.g., in the range of 30-40 microns in the case where the molding material to be used is PET). It should be noted that in the molded configuration, only the main vent 149 of vent 145 is relied upon to vent the mold cavity.

As shown in fig. 6, the gap forming the primary vent hole 149 is substantially orthogonal to the axis L of lateral separation of the two

halves

116, 118, while the gap forming the secondary vent hole 147 is parallel to the axis L of lateral separation of the two

halves

116, 118. The primary vent hole 149 and the secondary vent hole 147 may thus be considered to define an offset of the break line 143 between the split mold insert halves 116, 118. It should be appreciated that the orientation of these relative gaps allows the vent holes 145 to continue to function as vent holes (i.e., vent air while preventing the passage of melt) even if they are slightly separated from one another when the split mold insert halves 116, 118 are arranged in a residue cleaning configuration as described below.

Turning to fig. 7, the split mold insert 114 is shown in a perspective view with the split mold insert halves 116, 118 oriented such that their respective mating faces 190, 192 are visible. It should be understood that the view of fig. 7 is for illustrative purposes only, and that split mold insert halves 116, 118 are not actually used in this orientation.

As shown, the example vent 145 of the present embodiment includes a series of grooves 141 defined in the mating surfaces 192 of the split mold insert half 118. These grooves serve to guide the exhaust gases and to discharge them to the atmosphere. In other embodiments, such a groove need not be present.

As is apparent from the foregoing description, when the mating halves 136, 138 of the tapered male portion 132 of the split mold insert 114 are fully seated within the tapered female seat 130 (e.g., as shown in fig. 3), and an axial clamping force is applied to the mold stack 103, the split mold insert halves 116, 118 remain together in the molded configuration despite the application of opposing outward forces by the pressurized melt within the neck-finish region of the mold cavity 105.

Referring to fig. 3, 5 and 6, it can be seen that the tapered male portion 132 of the split mold insert 114 has a distal annular tongue 140, the distal annular tongue 140 being configured (e.g., shaped and sized) to be received within an annular groove 135 (fig. 4) defined in the cavity insert 106 of the tapered female seat 130. These two features define a tongue and groove connection at the junction 144 between the split mold insert 114 and the cavity insert 106. When cavity insert 106 and split mold insert 114 are in the molded configuration of fig. 3, junction 144 serves as or defines a parting line between cavity insert 106 and split mold insert 114. The term "parting line" refers to a junction between two mold stack components that prevents melt from passing therethrough and is not as undesirable or otherwise relied upon as a vent to vent gases.

In this example embodiment, a parting line is formed between the mating surfaces, which in this embodiment constitute the annular lip 133 of the cavity insert 106 and the inwardly projecting shoulder 142 of the split mold insert 114 (see, e.g., fig. 3). As described below, the interface 144 is designed to be adjustable between a molding configuration in which the mating faces contact one another to define a parting line of the mold cavity 105 (with the mold stack in the molding configuration), and a cleaning configuration in which the mating faces are separated to define a space therebetween that serves as an extension of the mold cavity 105, i.e., is part of the molding surface of the mold cavity 105 (when the mold stack 103 is in a residue cleaning configuration).

When the mold stack 103 is in the molding configuration, the split mold insert 114 and the lock ring 111 combine to define a vent 150 for venting air from the mold cavity 105 (see fig. 3). The vent 150 is located at or near the end of the melt flow path within the mold cavity 105. Because melt will be injected into the mold cavity 105 via the gate insert 107 (i.e., from the right in fig. 1 and 3) and will flow toward the neck 119 (i.e., to the left in fig. 1 and 3), the vent 150 will be in the final region of the mold cavity 105 reached by the injected melt. Because the advancing melt pushes air in front of it, the vent 150 may serve to vent any remaining air from within the mold cavity 105 near the end of the injection molding cycle, thus helping to promote molded article quality.

FIG. 8 provides a close-up view of a portion of the mold stack section of FIG. 3 with the vent 150 shown in greater detail. Referring to fig. 8, it can be seen that the vent 150 includes a primary vent 152 in fluid communication with a secondary vent 154. In fig. 8, the primary vent 152 appears as a vertical gap between the split mold insert 114 and the lock ring 111, and the secondary vent 154 appears as a horizontal gap between the same two components. In this embodiment, the vent 150 is defined in part by the split mold insert 114 and in part by the lock ring 111.

When the split mold insert 114 and the lock ring 111 are in the molded configuration as shown in fig. 8, the vent 150 is configured to vent air while preventing the passage of melt, i.e., allowing the passage of air from the mold cavity 105 without allowing the passage of any substantial amount of melt from the mold cavity 105. This may be achieved by appropriate sizing of the gaps of the primary and secondary vents 152, 154 (e.g. in the range of 30-40 microns where the moulding material to be used is PET). It should be noted that in the molding configuration, only the primary vent 152 of vent 150 is relied upon to vent the mold cavity.

As the mold 100 operates over multiple molding cycles, residue can accumulate within the main vent 152 of the vent 150 and also within the main vent 149 defined by the vent 145 (fig. 6) between the split mold insert halves 116, 118. The residue may for example consist of moulding material dust, contamination or other particles. In conventional molding systems, the removal of vent residue may be performed by: the molding system is taken out of operation, the mold stack is opened and the affected vent surfaces are manually scraped and/or cleaned. A possible disadvantage of this method is the corresponding loss of production capacity and the manual labor involved as well as a significant risk of damaging the mould.

To avoid the need for such conventional cleaning, the example mold stack 103 may be configurable between the standard cleaning configuration and the vented cleaning configuration described above. In the vent-cleaning configuration, the mold stack components that normally cooperate to define the vent holes therebetween are slightly separated from one another so as to sufficiently widen the primary vent hole for receiving melt from the mold cavity and still maintain the secondary vent holes to receive melt therein. In other words, the main vent to be cleaned is reconfigured as an extension of the mold cavity. When a molding cycle is conducted with the mold stack in the vent-cleaned configuration, melt from the mold cavity enters the enlarged vent as a "deliberate flash". The extent of flashing is controlled by the use of a backup or secondary vent designed to vent gas from the widened vent while preventing any substantial melt from passing therethrough. Residue in the vent to be cleaned (i.e., the primary vent) may be incorporated into the flash and, therefore, may be removed when the molded article is ejected from the mold cavity along with the integral flash. Such cleaning cycles may be scheduled as desired, for example at predetermined time intervals, after a predetermined number of molding cycles, or as desired.

This embodiment enhances the above-described exhaust gas cleaning method by additional flash areas that are not typically used as vents. The joint may be reconfigured to serve as an extension of the mold cavity by separating certain mold stack components that normally cooperate at the joint to define a parting line therebetween. The mold cavity extension has an auxiliary melt barrier (which may be an auxiliary vent) designed to accommodate flash evaporation within the extension. Thus, in the residue cleaning configuration of the present embodiment, controlled flashing occurs not only in the vent hole where the residue is to be cleaned, but also within at least one junction that typically serves as a parting line. The use of the foregoing is not very concerned with the necessity of cleaning the parting line of any excess residue therein, although this is not precluded, but rather requires opening the parting line to perform the repositioning of the vent holes 145, 150 and in doing so requires some means of control to contain the melt within the molding space defined between the normally contacting surfaces of the parting line and thereby precluding uncontrolled flashing of the mold stack.

Fig. 9-14 illustrate various aspects of an example mold 100 in a cleaning configuration. Fig. 9 is a cross-sectional elevation view of the same portion of the mold 100 shown in fig. 1, but with the core insert 110 omitted for clarity. FIG. 10 provides a close-up cross-sectional elevation view of a portion of FIG. 9, illustrating the interaction between the lock ring 111, split mold insert 114, cavity flange 109, and cavity insert 106 when the example cavity mold stack 103 is in a clean configuration. Fig. 11-14 are described below.

Fig. 9 differs from fig. 1 in that: the closing height S' of the mold 100 of fig. 9 is increased compared to the closing height S of the mold 100 of fig. 1. In the injection molding industry, the term "closure height" is generally used to refer to the distance between the end faces of the mold halves (which may or may not include melt distribution devices such as hot runners, omitted from the figures), i.e., the front face 113 of core plate 112 and the back face 155 of cavity plate 108. In fig. 9, the closing height has been increased to S' so that the mold stack 103 may be placed in a cleaning configuration. The increase in closure height may be achieved by various types of closure height adjustment mechanisms, none of which are specifically shown in any of fig. 1-14. An example closure height adjustment mechanism is described below.

Referring to fig. 9 and 10, it can be seen that the increase in closed height from S to S' is due to the introduction of gaps G1 and G2 on opposite sides of the split mold insert 114. A first gap G1 is between split mold insert 114 and lock ring 111, and a second gap G2 is between split mold insert 114 and cavity insert 106. It should be appreciated that due to the introduction of gaps G1 and G2, it is now possible to perform controlled flashing during a clean molding cycle in three regions of the mold stack 103 where flashing does not typically occur during a standard molding cycle.

The first region where controlled flash evaporation can now be performed due to the introduction of gap G1 is located within vent 150 between lock ring 111 and split mold insert 114, and specifically within the main vent 152 portion of the vent. Referring to fig. 11, it can be seen that in the cleaning configuration, the size (width) of the main vent 152 increases from the molded configuration size that prevents the passage of any substantial amount of melt (as shown in fig. 8) to an increased size that allows melt to enter the main vent 152 to incorporate and remove residue 160 (as shown in fig. 11). Notably, the dimensions of the secondary vent 154 in the cleaning configuration of fig. 11 remain the same or substantially the same as in the molded configuration (see fig. 8). Thus, the secondary vent 154 remains appropriately sized to vent gas (air) while substantially preventing the passage of melt. Indeed, the secondary vent 154 takes over the function of the primary vent 154 in this configuration, thereby preventing uncontrolled flashing.

Due to the introduction of gap G2, a second region where controlled flashing can now be performed is located within the junction 144 between the split mold insert 114 and the cavity insert 106. As shown in fig. 12, which provides a close-up cross-sectional view of the joint, it can be seen that the tongue 140 has been slightly withdrawn from the groove 135 in the cleaning configuration of the mold stack 103. In addition, the annular lip 133 (mating face) of the cavity insert 106 has been slightly separated from the inwardly projecting shoulder 142 (mating face) of the split mold insert 114 to define a space 146 therebetween. This space 146 serves as a cavity extension 146 of the mold cavity 105 that can receive melt.

Suitable dimensions of gaps G1 and G2 that allow melt to enter main vent 152 and cavity extension 146, respectively, may depend on the type of molding material used, but in the case of PET may be, for example, about 500 microns (0.5 millimeters).

Note that flashing of the cavity extension 146 does not serve residue cleaning purposes, as the joint 144 typically serves as a parting line rather than a vent. Thus, performing a controlled flash (or any type of flash) into the joint may be considered counterintuitive.

In the cleaning configuration, the junction 144 also defines an auxiliary melt barrier 151 to prevent uncontrolled flashing of the melt, i.e., containment of the melt within the cavity extension 146. The reason for containing the melt within the cavity extension is to reduce or eliminate the risk of flash inadvertently reaching adjacent components of the mold stack 103, where flash can interfere with smooth operation of the mold 100 during normal molding operations. In this embodiment, the auxiliary melt barrier 151 is an auxiliary vent adapted to vent gas while preventing any substantial amount of melt from passing through (e.g., similar to the auxiliary vent 154 of fig. 11).

In the present embodiment, the auxiliary vent 151 (fig. 12) is oriented substantially longitudinally (axially) with respect to the mold stack 103 (i.e., the auxiliary vent is substantially parallel to the longitudinal or operational axis of the mold stack 103 and thus the operational axis a of the mold 100). In contrast, the cavity extension 146 is oriented substantially laterally (radially) with respect to the mold stack 103 (i.e., the cavity extension 146 is substantially orthogonal to the longitudinal or operational axis of the mold stack 103). The auxiliary vent 151 and the cavity extension 146 of fig. 12 are thus substantially orthogonal to each other.

In alternative embodiments, the auxiliary melt barrier 151 may be configured such that it is not intended and does not otherwise rely on a parting line for use as a vent.

Also due to the introduction of gap G2, the third area where controlled flashing can now be performed is within the main vent 149 portion of vent 145 that splits between the mold insert halves 116, 118. Referring to fig. 10, 13 and 14, it can be seen that in view of the gap G2 (fig. 10) having been introduced between the split mold insert 114 and the cavity insert 106 (i.e., in view of the tapered male portion 132 partially receding from the tapered female seat 130), the split mold insert halves 116, 118 are free to laterally separate into a size suitable for flashing to occur within the main vent hole 149 (fig. 14). In other words, the lateral separation of the split mold insert halves 116, 118 along axis L (fig. 14) has increased the width of the main vent hole 149 sufficiently for the melt to enter. In contrast, the size of the secondary vent 147, which is substantially unchanged from its molded configuration size, still remains a suitable size for venting air without allowing any substantial amount of melt to pass through, i.e., remains substantially constant. Thus, the secondary vent 147 prevents uncontrolled flashing of the split mold insert halves 116, 118 when they are in the cleaning configuration shown in fig. 10, 13 and 14.

The tapered female seat 130 limits the degree of separation of the split mold insert halves 116, 118 by limiting the degree of separation of the associated

halves

136, 138 of the tapered male portion 132 (see fig. 10). Accordingly, the degree of separation of the split mold insert halves 116, 118 may be controlled by appropriately setting the gap G2, for example, by closing a height adjustment mechanism (such as the example mechanisms described below).

When the mold stack 103 is in the clean configuration shown in fig. 9-14, an injection molding cycle is performed and the product may be a preform 401 as shown in fig. 14A. Referring to this figure, it can be seen that the preform 401 has the appearance of a standard preform 101 (as shown in figure 2) with three

additional flash zones

403, 405 and 407 integrally formed with the preform 401. The first additional flash area 403 has the shape of a widened main vent 149 between the split mold insert halves 116, 118 (see fig. 14). The second additional flash zone 405 has the shape of the widened primary vent 152 between the split mold insert 114 and the lock ring 111 (see fig. 11). The third additional flash zone 407 has the shape of a cavity extension 146 formed between mating faces of the joint 144, i.e., between the inwardly projecting shoulder 142 of the split mold insert 114 and the lip 133 of the cavity insert 106 (see fig. 12).

In some embodiments, separation of split mold insert halves 116, 118 into a cleaning configuration may be accomplished using a closed height adjuster (not shown) or by controlling the applied clamp tonnage, as described in commonly assigned patent publication WO 2014/117246.

As described above, the example mold stack 103 shown in fig. 1-14 is a cavity lock mold stack. It should be understood that other types of mold stack types may be similarly configured to accommodate the cleaning configuration.

For example, referring to FIG. 15, there is shown another embodiment of a mold 300 in which the mold stack is a core lock type. Fig. 15 is a cross-sectional view of a mold 300 capable of producing a molded article, i.e., a preform similar to the preform shown in fig. 2. The portion of the mold 300 shown in fig. 15 is a longitudinal cross-sectional view of a single mold stack 303 used to make a single preform 301. As shown in fig. 15, the mold stack 303 is depicted in a production or molding configuration.

The exemplary mold 300 of fig. 15 includes a pair of mold halves that are relatively movable along an operational axis a. The first mold half includes a cavity plate assembly 302. The second mold half includes a core plate assembly 304 and a stripper plate assembly 325 movable relative to and along the operating axis a.

Cavity plate assembly 302 includes a cavity insert 306 and a gate insert 307 retained by a cavity flange 309. In alternative embodiments, cavity piece 306 and gate insert 307 may form a portion of plate 308 and/or may comprise a single component.

Core plate assembly 304 includes: a core insert 310; a lock ring 311 configured to support the core insert 310 and to help align and hold closed a split mold insert 314 (described below); a core ring 339 configured to define part of a top sealing surface of a preform to be molded, and to be combined with the split mold insert 314; a core ring to split insert parting line within a recess of a split mold insert; and a core plate 312, core insert 310 and lock ring 311 are attached to core plate 312.

Stripper plate assembly 325 comprises stripper plate 320, slide bars 322, 323 slidably coupled to stripper plate 320, and split mold insert 314 for defining a neck finish of a preform to be molded. The split mold insert 314 comprises a pair of complementary split mold insert halves 316, 318 attached to slide

bars

322, 323, respectively. As shown in fig. 15, the mold 300 has an operational axis a that is parallel to the longitudinal axis of the mold stack 303. The axis a may also be considered an operational axis of the mold stack 303.

The mold stack 303 shown in FIG. 1 is referred to as a "core lock" type mold stack. This term reflects one of the following designs: wherein the split mold insert halves 316, 318 are "locked" together laterally (vertically in fig. 1) as clamping pressure is applied axially to the mold stack 303 due, at least in part, to the tapered male portion being closely seated within the seat defined by the lock ring 311 and the core ring 339 of the mold stack 303. This relationship is shown in more detail in fig. 16.

Referring to FIG. 16, a close-up cross-sectional elevation view of a portion of the mold stack 303 of FIG. 15 is depicted. Fig. 16 illustrates the interaction between the lock ring 311, the core ring 339, the split mold insert 314, the cavity flange 309, and the cavity insert 306 when the example cavity mold stack 303 is in a molding configuration. In fig. 16, the core insert 310 of fig. 15 is omitted for clarity.

As shown, the cavity flange 309 and the cavity insert 306 combine to define a tapered concave seat 330 having a generally frustoconical shape. Adjacent split mold inserts 314 have a tapered male portion 332 of complementary shape (i.e., generally frustoconical), which allows the tapered male portion 332 to be closely received within the tapered female seat 330 when the split mold insert 314 and cavity insert 306 are in a mating molded configuration. Referring to fig. 16 in conjunction with fig. 17, the shape of these features may be best seen, and fig. 17 provides a perspective view of the tapered male portion 332.

Referring to FIG. 16, it can be seen that cavity flange 309 has an inwardly tapered wall 329, with tapered wall 329 terminating at a parting line 331 formed between cavity flange 309 and cavity insert 306. The cavity insert 306 defines an annular groove 335 at the deepest portion of the tapered female seat 330. In this embodiment, an annular groove 335 is formed between a central annular lip 333 in the end of the cavity insert 306 and a peripheral wall 337 of the cavity insert 306, the taper of the peripheral wall 337 matching the taper of the wall 329 of the cavity flange 309. The configuration of these features may be similar to the corresponding features of the cavity insert 106 and cavity flange 109 of the previously described embodiments (see fig. 4).

Referring also to fig. 16, it can also be seen that the lock ring 311 defines another tapered female seat 370 opposite the first tapered female seat 330 described above. The tapered female seat 370 has a shape complementary to a second tapered male portion 380 of the split mold insert 314 that extends away from the cavity 308. The lock ring 311 and core ring 339 may be considered to jointly define an annular recess 395 into which the tapered male portion of the split mold insert 314 may be closely received.

Turning to FIG. 17, in conjunction with FIG. 18, a split mold insert 314 isolated from other mold stack components is shown in perspective and elevation views, respectively. In each of fig. 17 and 18, the split mold insert 314 is shown in a molded configuration with its

halves

316, 318 mated. The visible tapered male portion 332 of the insert 314 is separated by a break line 343, a first half 336 of the male portion 332 forming part of the split mold insert half 316, and a second half 338 of the male portion 332 forming part of the split mold insert half 318. The other tapered male portion 380 is not visible in fig. 1 and 2, but similarly splits.

As shown, the split mold insert halves 316, 318 jointly define a vent 345 therebetween, which vent 345 may be similar to the vent 145 of the previous embodiment. The vent 345 includes a primary vent 349 (horizontally oriented in fig. 18) in fluid communication with a secondary vent 347 (vertically oriented in fig. 18). Each of the primary and secondary vents of the present embodiment includes a gap between split mold insert halves 316, 318. When the split mold insert 314 is in the molded configuration as shown in fig. 17 and 18, the vent 345 is configured to vent air from the mold cavity 305 while preventing any substantial amount of melt from passing therethrough. This may be achieved by appropriate sizing of the gaps comprising each of the primary vent 349 and the secondary vent 347.

As shown in fig. 18, the gap forming the primary vent 349 is orthogonal to the axis L of the lateral separation of the two

halves

316, 318, while the gap forming the secondary vent 347 is parallel to the axis L. These opposing gap orientations will allow the vent 345 to continue to function as a vent (i.e., vent air while preventing the melt from passing), even when the

split mold halves

316, 318 are slightly separated from each other. It should be noted that in the molded configuration, only the primary vent 349 of vent 345 is relied upon to vent the mold cavity.

Turning to fig. 18A, the split mold insert 314 is shown in perspective view with the split mold insert halves 316, 318 oriented such that their respective mating faces 390, 392 are visible. It should be understood that the view of fig. 18A is for illustration only, and that split mold insert halves 316, 318 are not actually used in this orientation. As shown, the example vent 345 of the present embodiment includes a series of recesses 341 defined in a mating face 392. These grooves serve to guide the body to be evacuated and to discharge it to the atmosphere. In other embodiments, such a groove need not be present.

Fig. 18A shows a second tapered convex portion 380 that is not visible in fig. 17 and 18. As shown, the tapered male portion 380 is also split off the split line 343, with a first half 386 of the male portion 332 forming part of the split mold insert half 316 and a second half 388 of the male portion 332 forming part of the split mold insert half 318.

It should be appreciated that when the mating halves 336, 348 of the tapered male portion 332 of the split mold insert 314 are located within the tapered female seat 330 and the mating halves 386, 388 of the tapered male portion 380 of the split mold insert 314 are located within the tapered female seat 370 (e.g., as shown in fig. 16), and an axial clamping force is applied to the mold stack 303, the split mold insert halves 316, 318 remain together in the molded configuration despite the opposing outward force applied by the pressurized melt within the neck finish region of the mold cavity 305.

Referring to fig. 17 and 18, it can be seen that the tapered male portion 332 of the split mold insert 314 has a distal annular tongue 340, the distal annular tongue 340 being configured (e.g., shaped and sized) to be received within an annular groove 335 defined by the cavity insert 306. These two features combine to define a tongue and groove connection in the junction between the split mold insert 314 and the cavity insert 306. When cavity insert 306 and split mold insert 314 are in the molded configuration of fig. 16, joint 344 serves as or defines a parting line between cavity insert 306 and split mold insert 314. In the exemplary embodiment, a parting line is formed between an annular lip 333 (mating surface) of cavity insert 306 and an inwardly projecting shoulder 342 (mating surface) of split mold insert 314. The joint 344 is designed to be adjustable between a molding configuration in which the mating faces contact one another to define a parting line of the mold cavity 305 (with the mold stack in the molding configuration), and a cleaning configuration in which the mating faces are separated to define a space therebetween that serves as an extension of the mold cavity 305, i.e., is part of the molding surface of the mold cavity 305 (when the mold stack 303 is in the vent cleaning configuration).

When the mold stack 303 is in the molding configuration of fig. 16, the split mold insert 314 and the core ring 339 jointly define a vent 350 therebetween, the vent 350 serving to vent air from the mold cavity 305 without allowing any substantial melt to pass through. This is shown in more detail in fig. 18B.

As shown in fig. 18B, the vent 350 of the present embodiment is formed on the split line between the core ring 339 and the recessed face 358 (distal of the recess relative to the tapered male portion 380) of the split mold insert 314. Vent 350 is located in a recess 353 formed in split mold insert 314 for receiving the end of core ring 339, the recess 353 being coaxial with tapered male portion 380. The vent 350 includes a primary vent 352 in fluid communication with a secondary vent 354. In fig. 18B, the primary vent 352 represents a vertical gap between the split mold insert 314 and the core ring 339, and the secondary vent 354 represents a horizontal gap between the same two components.

When the split mold insert 314 and core ring 339 are in the molded configuration as shown in fig. 18B, the vent 350 is configured to vent air while preventing the passage of melt, i.e., allowing air to pass from the mold cavity 305 without allowing any substantial amount of melt to pass from the mold cavity 305. This may be achieved by appropriate sizing of the gaps of the primary and secondary vents 152, 154 (e.g. in the range of 30-40 microns where the moulding material to be used is PET). It should be noted that in the molded configuration, only the primary vent 352 of vent 350 is relied upon to vent the mold cavity.

Because the primary vent hole 352 is oriented orthogonal to the operational axis of the mold stack 303 and the secondary vent hole is parallel to the operational axis of the mold stack 303, the primary vent hole 352 may be widened while the width of the secondary vent hole 354 remains substantially constant when the mold stack 303 and/or the mold 300 is placed in the cleaning configuration. Thus, when the mold stack 303 is in the cleaning configuration, the secondary vent 354 may continue to serve as a vent for air without allowing any significant amount of melt to pass through.

Fig. 19-23 illustrate various aspects of an example mold 300 and mold stack 303 in a clean configuration. Fig. 19 is a sectional elevation view showing the same portion of the mold 300 as shown in fig. 15, but with the core insert 310 omitted for clarity. Fig. 20 provides an approximate cross-sectional elevation view of a portion of fig. 19, illustrating the interaction between the lock ring 311, the core ring 339, the split mold insert 314, the cavity flange 309, and the cavity insert 306 when the example core-lock mold stack 303 is in a clean configuration. Fig. 21-23 are described below.

In fig. 19, the closed height of the system 300 of fig. 15 is increased to S' by introducing gaps G1 and G2 on opposite sides of the split mold insert 314. A first gap G1 is between split mold insert 314 and lock ring 311/core ring 339, and a second gap G2 is between split mold insert 314 and cavity insert 306. Due to the introduction of gaps G1 and G2, it is now possible to perform controlled flashing in three regions of the mold stack 303 during a clean molding cycle, where flashing would not normally occur in a standard molding cycle.

By introducing the gap G1, it is now possible to perform controlled flashing of the first region within the vent holes 350 between the core ring 339 and the split mold insert 314, in a manner similar to the vent holes 150 of fig. 11 discussed above.

By introducing the gap G2, the second region where controlled flashing can now be performed is within the junction 344 between the split mold insert 314 and the cavity insert 306. Referring to fig. 23, it can be seen that in the cleaning configuration of the mold stack 303, the tongue 340 has been slightly withdrawn from the groove 335. Further, the annular lip 333 (mating face) of the cavity insert 306 is slightly separated from the inwardly projecting shoulder 342 (mating face) of the split mold insert 314. This reconfigures the joint 344 to define a space 346 between the mating surfaces 333, 342, the space 346 serving as an extension of the mold cavity 305 capable of receiving melt. Note that flashing of the cavity extension region 346 does not serve residue cleaning purposes, as the joint 344 generally serves as a parting line rather than a vent.

In the cleaning configuration, the junction 344 also defines an auxiliary melt barrier 351 to prevent uncontrolled flashing of the melt, i.e., the melt is contained within the cavity extension 346. In this embodiment, the auxiliary melt barrier 351 is an auxiliary vent hole 351 sized to be suitable for venting gas while preventing melt from passing therethrough. The auxiliary vent 351 (fig. 23) is oriented substantially longitudinally (axially) with respect to the mold stack 303 (i.e., the auxiliary vent is substantially parallel to the longitudinal or operational axis of the mold stack 303 and substantially parallel to the operational axis a of the mold 300). This is in contrast to the cavity extension 346, which cavity extension 346 is oriented substantially laterally (radially) with respect to the mold stack 303 (i.e., the cavity extension 346 is substantially orthogonal to the longitudinal or operational axis of the mold stack 303). Accordingly, the auxiliary vent 351 and the cavity extension 346 are substantially orthogonal to each other.

By introducing gaps G1 and G2, a third region where controlled flashing can now be performed is within the portion of the primary vent 349 that splits off the vent 345 between the mold insert halves 316, 318. Referring to fig. 20, 21 and 22, it can be seen that in view of having introduced a gap G1 (fig. 20) between the split mold insert 314 and the core ring 339 (i.e., in view of the tapered male portion 380 partially receding from the tapered female seat 330) and further in view of having introduced a gap G2 (fig. 20) between the split mold insert 314 and the cavity insert 306 (i.e., in view of the tapered male portion 332 partially receding from the tapered female seat 330), the split mold insert halves 316, 318 are free to laterally separate into a size suitable for flash vaporization to occur within the primary vent 349. In other words, the lateral separation of split mold insert halves 316, 318 along axis L (fig. 22) has increased the width of primary vent 349 sufficiently for melt to enter. In contrast, the size of the secondary vent 347 generally remains constant, with the size of the secondary vent 347 being suitable for venting air without allowing any significant amount of melt to pass through. Thus, the secondary vent 347 prevents uncontrolled flashing when the split mold insert halves 316, 318 are in the clean configuration shown in fig. 20, 21, 22.

As shown in fig. 20, the tapered female seat 370 limits the degree of separation of the split mold insert halves 316, 318 by limiting the degree of separation of the associated halves of the tapered male portion 380, and the tapered female seat 330 limits the degree of separation of the split mold insert halves 316, 318 by limiting the degree of separation of the associated

halves

336, 338 of the tapered male portion 332. The degree of separation of the split mold insert halves 316, 318 may thus be controlled by appropriately setting the gaps G1 and G2, which may be set at G1 and G2, for example, via a closure height adjustment mechanism (not shown), or by controlling the applied clamp tonnage, as described in commonly assigned patent publication WO 2014/117246.

As shown above with respect to fig. 9 and 20, the closed height of the mold may be adjusted using a closed height adjustment mechanism so that the mold stack may be placed in a cleaning configuration. In fig. 24-45, a mold 500 is shown that includes a closure height adjustment mechanism that can be used for this or other purposes.

Referring to fig. 24, an example mold 500 is shown in a side elevation view. This particular mold 500 is designed to mold 144 preforms in bulk in a single molding cycle (i.e., the mold contains a total of 144 mold stacks). In other embodiments, the type and number of molded articles may vary.

The example mold 500 includes a cavity plate assembly 502, a stripper plate assembly 525, and a core plate assembly 504, each movable relative to one another. Fig. 24 also shows the spacer assembly 590 secured to the core plate assembly 504.

The left and right sides of the mold as shown refer to the front and back (or rear) sides of the mold 500, respectively. This convention is used for convenience and does not necessarily imply any particular orientation of the mold 500 during use. For consistency, the same convention is used throughout the description of the mold 500 and its components, i.e., throughout fig. 24-45.

Fig. 25 and 26 show a cavity plate assembly 502 of a mold 500 in a rear and front perspective view, respectively. As shown, the cavity plate assembly 502 includes a cavity plate 508 having eight vertical rows of a plurality of cavity inserts 506 of 18 cells each (i.e., 144 cells total). Each cavity insert 506 is held in place by a respective cavity flange 509 (fig. 26) attached to the front face of the cavity plate 508. A plurality of tonnage blocks 513 are mounted to the front side of the cavity plate 508. As is known in the art, tonnage blocks can be used to withstand some clamping force applied to the mold to avoid applying excessive force and possible damage to the mold stack within the mold. In a standard molding configuration, tonnage blocks 513 may be used to transfer forces between the cavity plate 508 and the stripper plate 520. The height of the tonnage block can be selected to provide an appropriate or desired distance between the cavity plate 508 and the stripper plate 520 in this configuration. As will be appreciated, in the vent cleaning configuration, the tonnage blocks 513 will bypass both the stripper plate 520 and the core plate 512 via stop members 560 (described below) instead of transferring force between the cavity plate 508 and the spacer frame 594. In the embodiment shown in FIG. 26, the tonnage blocks 513 are arranged in seven columns to fit between eight columns of cavity inserts 506 on the cavity plate 508.

Fig. 27 and 28 show a stripper plate assembly 525 of the mold 500 in rear and front perspective views, respectively. As shown, stripper plate assembly 525 includes a stripper plate 520 having eight pairs of slide bars 522, 523 slidably coupled thereto. The slide bar is oriented substantially vertically in fig. 27. Each pair of slide bars has eighteen split mold inserts 514 attached thereto, with each split mold insert half 516, 518 attached to a respective one of a pair of slide bars 522, 523. Each pair of slide bars 522, 523 reciprocate relative to each other in a generally horizontal direction, e.g., for releasing the neck finish of a molded preform. Three pairs of substantially horizontal connecting

rods

577, 578 are coupled to and can be used to drive coordinated reciprocating motion of all pairs of sliding rods.

Stripper plate assembly 525 further includes a plurality of stop members 560 (fig. 28) slidably received within corresponding apertures in stripper plate 520. The stop member 560 is part of a closure height adjustment mechanism for selectively increasing the closure height of the mold 500, for example, for placing the mold stack in a cleaning configuration. As shown in fig. 28, the present embodiment includes a total of twenty-eight stop members 560 distributed throughout the area of the plate 520. The use of multiple stop members 560 allows the mold clamping force to be distributed between them and may reduce the risk of damaging individual stop members or bending of the plate 520. An example stop member 560 is shown in fig. 29. For clarity, reference numeral 560 is used herein to refer not only to the stop member 560 uniformly but also generically.

Referring to fig. 29, an example stop member 560 is shown in a perspective view. When the mold 500 achieves the standard closing height S, e.g. during normal molding operation of the mold 500, the stop member is intended to be retracted and, e.g. during cleaning operation of the mold 500, to be deployed in order to achieve an increased closing height S' of the mold 500. In particular, the stop member is designed to increase the closed height of the mold by providing a gap on either side (front and back) of the mold part, which in this example embodiment is a stripper plate 520. To this end, the stop member 560 has two stops, i.e., features that act as or define stops when the stop member is deployed. It should be understood that the first stop is designed to provide a first gap (G1) at the front side of the stripper plate and the second stop is designed to provide a second gap (G2) at the back side of the stripper plate.

The example stop member 560 of the present embodiment takes the form of a cylindrical pin. The stop member in alternative embodiments may have a different shape. The pin has two

ends

570, 572 which, in this embodiment, may be the leading end 570 and trailing end 572, respectively, of the stop member 560, and each are substantially flat. The stop member 560 has a front 566 and a rear 564. The front portion 566 defines a first stop of the stop member 560, and the rear portion 564 defines a second stop of the stop member 560.

The forward portion 566 of the stop member 560 extends from the head end 570 of the stop member to and includes a radial flange 568, the radial flange 568 being in the form of a protrusion in the stop member 560. The radial flange 568 is a feature of the present stop member embodiment that serves as or defines a first stop. The front portion 566 of the stop member 560 is sized to be slidably received within the bore by an adjacent core plate (described below). The front portion 566 has a length L2 (measured from the back face 565 of the radial flange 568 to the head end 570 of the stop member 560) that is slightly greater than the thickness T2 of the core plate.

The rear portion 564 of the stop member 560 extends between the trailing end 572 of the stop member and the first stop and is configured (sized and shaped) to be slidably received within the corresponding aperture 562 by the stripper plate 520. The rear portion 564 has a length L1, measured from a back face 565 of the radial flange 568 to a trailing end 572 of the stop member 560. The length L1 is slightly greater than the thickness T1 of the peel plate 520. Thus, when the stop member 560 is inserted into the hole 562, and when the first stop (here, the back face 565 of the radial flange 568) engages the front side 567 of the stripper plate 520 (in view of the fact that the flange 568 is wider than the hole 562), the trailing end 572 of the stop member 560 will be disposed slightly above the rear side 569 of the stripper plate 520, i.e., projecting slightly from the rear side 569 of the stripper plate 520. As will be appreciated, the trailing end 572 of the tab will act as a second stop, providing a gap G2 (fig. 45) on the rear side 569 of the stripper plate 520.

In this embodiment, the diameter of the front portion 566 is greater than the diameter of the rear portion 564. The relative dimensions may be dictated by geometric or dimensional constraints dictated by adjacent components of the mold 500. The diameters of the front and rear portions of alternative embodiments may be the same or different.

The rear portion 564 of the example stop member 560 of fig. 29 has a plurality of

circumferential grooves

555, 557, 559. Circumferential groove 555 (which may be considered a single step diameter of rear portion 564) may divert stress in the stop member away from groove 557 under axial compressive loads. This may avoid excessive stress that may cause the stop member 560 to yield. Separating grooves 555 and 557 a distance may facilitate this effect at the possible expense of the stopper member tilt avoidance effect, as described below.

The

circumferential grooves

557, 559 may each receive an O-ring. The O-ring may not be for sealing but may be used to inhibit or limit axial movement of the stop member 560 when stowed. The O-ring may be designed to facilitate a fit between stop member 560 and hole 562 in stripper plate 520, which may advantageously reduce or eliminate wobble of stop member 560 within hole 562 because mold 500 is used for standard molding purposes. This may reduce or eliminate impact loading on the radial flange 568, which in turn may reduce the risk of damage to the radial flange 565. The O-ring may alternatively or in combination limit the descent/tilt of the stop member 560 within the bore 562 so that when the stop member 560 is axially loaded, the stop member 560 does not apply a significant load to the edge before straightening. The latter can potentially impart a high degree of load to the spacer frame 594 tonnage blocks 513. The groove/O-ring may also help center the stop member 560 within the bore 562 to facilitate its alignment with the spacer 598. In some embodiments, to provide similar benefits, circumferential grooves may alternatively be added into the holes 562 in the stripper plate 520. The latter may be more difficult to manufacture than the former and may complicate O-ring installation.

Referring also to fig. 29, it can be seen that the stop member 560 has an associated retaining pin 580 in the form of a retaining mechanism. The retaining pins 580 function to retain the stop member 560 with the stripper plate 520 during use, i.e., to prevent the stop member 560 from backing out of the bore 562 during operation of the die 500. The example retaining pin 580 of this embodiment includes a fastener 582 having a threaded end 584 and a radial lip 586. The threaded end 584 is designed to threadably engage a corresponding threaded hole 588 in the stripper plate 520.

The retaining pin 580 and the stripper plate 520 in combination define the range of motion (axial play) of the radial flange 568 of the stop member 560. The forward extent of this range is defined by contact between the front face of the radial flange 568 and the back face of the radial lip 586. The rearward extent of this extent is defined by the contact between the back face of the radial flange 568 and the front face of the stripper plate 520. Thus, the retaining pin 580 and the stripper plate 520 in combination define a range of axial play of the stop member 560 relative to the stripper plate 520 along the operational axis of the die 500.

Fig. 30 and 31 show a core plate assembly 504 of the mold 500 in rear and front perspective views, respectively. Referring to these figures, it can be seen that core plate assembly 104 includes a core plate 512 having a plurality of core inserts 510 and corresponding lock rings 511 projecting therefrom. The core inserts 510 and corresponding lock rings 511 are arranged in eight generally vertical rows of eighteen units each to correspond to the arrangement of split mold inserts 514 on stripper plate 520 and cavity inserts 506 on cavity plate 508.

Core plate 512 also includes a plurality of apertures 530, each configured to slidably receive a front portion 566 (fig. 29) of a corresponding stop member 560. In the present embodiment, the number of holes 530 passing through the core plate 512 corresponds to the number of stop members 560, i.e., twenty-eight. This number may vary between embodiments.

On the back of the core plate 512 (fig. 30), a keyhole-shaped dimple 532 surrounds each aperture 530. This depression 532 accommodates both the radial flange 568 of the stop member 560 and the retaining pin 580 associated with the stop member 560.

It should be noted that other holes may be formed through core plate 512 in addition to holes 530, and may be used for other purposes (e.g., to accommodate stripper pins used during stripping of molded articles). These are not at the heart of this description.

Fig. 32 and 33 show the spacer assembly 590 components of the mold 500 in rear and front perspective views, respectively. The spacer assembly 590 includes a spacer back plate 592 and a spacer frame 594, the spacer frame 594 being located within a complementary shaped recess 596 in the back face of the spacer back plate 592. The spacer frame 594 interconnects a plurality (here, twenty-eight) of the spacers 598 into a unitary planar unit. Each spacer 598 is associated with a respective stop member 560. Spacer frame 594 is reciprocally movable within recess 596 between outboard and inboard positions under the control of actuator 599 (which may be, for example, a pneumatic or hydraulic actuator). In the outboard position shown in fig. 32, when the mold is used in a standard molding configuration, the spacers 598 are misaligned with their corresponding stop members 560, making room for the head ends 570 of the stop members 560 within the recesses 596. In the inboard position shown in fig. 41, the spacers 598 are aligned with their corresponding stop members 560 to deploy the stop members 560 to their deployed positions in which the annular flange 568 and the trailing end 572 of each stop member define a respective stop, as will be described.

Fig. 34 is an exploded view of a portion of a mold 500 showing the relationship between a single example stop member 560 and various nearby mold components. Fig. 34 may be considered to include the closure height adjustment mechanism 501 (or a portion thereof) of the present embodiment. As shown, the rear portion 564 of the stop member 560 is configured to be slidably received within the aperture 562 in the stripper plate 520. The threaded end 584 of the retaining pin 580 is configured for threaded threading into the threaded hole 588 for retaining the stop member 560 with the stripper plate 520. The trailing end 572 of the stop member 560 is flat. This shape is suitable for abutting a tonnage block extending from the front side of the cavity plate 508.

The front portion 566 of the stop member 560 is configured to be slidably received within the aperture 530 in the core plate 512. The keyhole-shaped depression 532 in the back face of the core plate 512 is sufficiently deep to accommodate both the radial flange 568 of the stop member 560 and the retaining pin 580 when the core plate 512 and the stripper plate 520 abut (the main circular region of the depression 532 accommodates the radial flange 568 and the neck region 533 accommodates the retaining pin 580). The stop members 560 are aligned with the recesses 596 in the spacer plate 592. Depending on whether the spacer 598 within the recess 596 is in the outboard position (as shown in fig. 34) or the inboard position, the end 570 of the stop member 560 will either be freely received within the recess 596 or will abut the spacer 598, respectively.

Operation 4600 for increasing the closed height of mold 500 is shown in flow chart form in fig. 46. Assume that the mold is initially in a standard molding configuration, as shown in fig. 24. Referring to fig. 35, a cross-sectional view of an example stop member 560 and nearby components is shown when the mold 500 having a closed height S is in a standard molding configuration.

When the mold 500 is in the standard molding configuration, the stop member 560 is in the stowed (non-deployed) position, as shown in fig. 35. In the stowed position, the stop member 560 is fully received within the joint space formed by: holes 562 through the stripper plate 520; a hole 530 through core plate 512; and a recess 596 behind the core plate 512. More specifically, the front portion 566 (shown separated from the rear portion 564 by dashed line B in fig. 35) of the stop member 560 is contained primarily within the bore 530 and partially within the recess 596, and the rear portion 564 of the stop member 560 is contained primarily within the bore 562 and partially within the bore 530. As shown in fig. 35, when the stop member 560 is in the stowed position, it does not prevent the stripper plate 520 from abutting against either the core plate 512 or the tonnage block 513 attached to the cavity plate 508 (the latter not shown in fig. 35). In the stowed position, neither the axial flange 568 nor the trailing end 572 act as a stop.

As shown in fig. 35, when the stop member 560 is in the stowed position, the trailing end 572 of the stop member 560 abuts or is proximate to the tonnage block 513. The reason is that when the tonnage blocks 513 are abutted against the stripper plate 520 in preparation for the molding cycle, the stop members 560 will be pushed forward into the stowed position. The head end 570 of the stop member 560 is in the free space within the recess 596. This occurs because the combination of the length L1 of the rear portion 564 of the stop member 560 and the length L2 of the front portion 566 of the stop member 560 exceeds the combined thickness of the core plate 512 and the stripper plate 520. In fig. 35, the spacer 598 is in the outboard position, misaligned with the stop member 560.

In operation 4602 (fig. 46), the mold 500 is opened. In this embodiment, opening the mold includes moving the platen 506, core plate assembly 504, and stripper plate assembly 525 jointly forward along the operational axis of the mold 500 away from the cavity plate assembly 502. The stripping plate 520 is thus moved forward away from the tonnage block 513 (fig. 37).

In operation 4604 (fig. 46), relative movement is provided between the stop member 560 and the spacer 598 along the operational axis of the mold 500 until the stop member 560 clears the spacer 598. In this embodiment, this is accomplished by moving the stripper plate assembly 525 back away from the core plate assembly 504 (fig. 38). When the stripping plate 520 is moved rearward, the stop members 560 will be retained with the stripping plate 520 by their respective retaining pins 580 (FIG. 39). The rearward movement of the stripper plate assembly 525 is sufficient to cause the head end 570 of the stop member 560 to clear the spacer 598.

In operation 4606 (fig. 46), the actuators 599 of the spacer assembly 590 are actuated to translate the spacer frame 594 from the outboard position to the inboard position within the recesses 596 of the spacer back plate 592 (fig. 40, 41). Accordingly, the spacer 598 moves from an outboard position out of alignment with the stop member 560 to an inboard position in alignment with the stop member 560 (fig. 42).

In operation 4608 (fig. 46), relative movement is provided between the stop member 560 and the spacer 598 along the operational axis of the mold until the spacer 598 blocks the stop member and thereby deploys it to the deployed position. In this embodiment, this is accomplished by moving the stripper plate assembly 525 forward toward the core plate assembly 504 (fig. 43). This is done until the head end 570 of the stop member 560 contacts, engages, or abuts the spacer 598 (fig. 44). The blocking of the spacer 598 prevents forward movement of the stop member 560.

The length L2 of the front portion 566 of the stop member 560 is such that when the spacer 598 blocks the stop member 560, a portion of the front portion 566 (here, a portion of the radial flange 568) is located above the back face of the core plate 512.

In operation 4610 (fig. 46), relative motion is provided between the stripper plate 520 and the deployed stop member 560 until the first stop of the deployed stop member engages the stripper plate 520. In the present embodiment, this is achieved by: the peel plate 520 continues to be moved forward a short distance with the aperture 562 sliding around the rear portion 564 of the stop member 560 stopped until the first stop (radial flange 568) engages the peel plate 520. It will be appreciated that this engagement will prevent forward movement of the stripper plate 520.

When the first stop has engaged the stripper plate 520, it will provide a first gap G1 on the front side of the stripper plate 520. In the present embodiment, this is due to the fact that: radial flange 568 is positioned over the back face of core plate 512 such that a gap G1 will be defined between core plate 512 and stripper plate 520.

Further, the second stop of the deployed stop member 5600 is now positioned to provide a second gap G2 on the back side of the stripping plate 520. In particular, in the present embodiment, since the length L1 of the rear portion 564 of the stop member 560 slightly exceeds the thickness T1 of the stripper plate 520, the trailing end 572 of the stop member 560 is located above the back of the stripper plate 520.

Finally, in operation 4612 (fig. 46), the mold 500 is closed, i.e., the platen 506, the core plate assembly 504, and the stripper plate assembly 525 are all moved back toward the cavity plate assembly 502 along the operational axis of the mold 500. This rearward movement will be prevented when the trailing end 572 of the stop member 560 contacts the tonnage block 513. Because the trailing end 572 of the stop member 560 is above the back of the stripper plate 520, as described above, a gap G2 will be created between the tonnage blocks 513 and the stripper plate 520 on the back side of the stripper plate 520. As a result, the closed height of the mold is now increased to S' equal to the original closed height S plus the sum of the two gaps G1 and G2.

When the mold 500 is in this configuration, any mold clamping force applied to the mold 500 will be transferred through the stop members 560, spacers 598, spacer plates 592 into the platen 506, and will bypass the stripper plate 520 and core plate 512. If desired, the mold stack in the mold 500 may be placed in a clean configuration when the mold 500 is in the configuration shown in fig. 46, similar to that discussed above in connection with fig. 10 and 20.

As will be appreciated, the closure height adjustment mechanism described above uses a stop member (or multiple instances thereof) for defining a gap on both sides of the mold component, which in this case is a stripper plate. Such a mechanism may eliminate the need for two separate mechanisms for defining each of the two gaps. This may reduce the complexity and/or cost of the mold. Further, the closure height adjustment mechanism is easily reconfigured to simply define the different sizes of gaps G1, G2, or both, by replacing each stop member with a new stop member having a longer or shorter rear portion, a longer or shorter front portion, or both.

The operations of method 4600 (fig. 46) are essentially repeated with three exceptions in order to reduce the mold 'S closed height from S' to S.

First, in operation 4606, the spacer 598 is moved from the inboard position to the outboard position, but not vice versa.

Next, in

operations

4608 and 4610, relative movement is provided between the stop member 560 and the spacer 598 along the operational axis of the mold until the head end 570 of the stop member 560 enters the recess 596 in the spacer plate 590. In particular, when the stripper plate assembly 525 is moved forward such that the stripper plate 520 engages the first stop 568 of the stop member 560, rearward movement of the stripper plate assembly 525 will not necessarily be prevented. This is in view of the outboard position of the spacer 598, in view of the free space within the recess 596 forward of the stop member 560. Instead, stripper plate 520 will push the first stop (radial flange 568) of stop member 560 flush with the back face of core plate 512 and will abut core plate 512. Thus, the first stop of the stop member 560 will not engage the stripping plate 520.

Third, when the tonnage block 513 engages the trailing end 572 of the stop member 560 when the mold is closed in operation 4612, rearward movement of the cavity plate 508 will not necessarily be prevented. Conversely, the cavity plate 508 will push the stop member 560 against the stripper plate 520 and core plate 512 in view of the free space within the recess 596 forward of the stop member 560 until the front of the cavity plate 508 abuts the back of the stripper plate 520. In other words, because the stop member 560 is not in the deployed position (i.e., the spacer 598 and its immediately adjacent back plate 590 block unhindered movement), the second stop of the stop member 560 (trailing end 572) does not function to provide the second gap G2. As a result, the stop member 560 will again reach its stowed position, as initially shown in fig. 35, and the closure height will return to the original closure height S.

Various alternative embodiments are possible.

In the split mold insert 114 described above, the vent 145 defined between the split mold insert halves 116, 118 includes a recess (e.g., a groove) formed in the mating surface 192 of the first split mold insert half 116. Similarly, the vent 345 defined between the split mold insert halves 316, 318 of the mold stack 303 includes only a recess formed in the mating face 392. It should be understood that in alternative embodiments, such recesses and/or grooves may be present in the opposing mating surfaces 190 or 390 of the other split mold insert halves 118 or 318, respectively or in addition.

In the closed height adjustment mechanism described above, the trailing end 572 of the stop member 560 engages the tonnage block 513 attached to the cavity plate 508 when the mold 500 is in the increased closed height configuration. It should be appreciated that in an alternative embodiment, the trailing end of the stop member may directly engage the cavity plate 508, for example, if the mold lacks a tonnage block 513.

The above-described closure height adjustment mechanism may be used without the above-described residue cleaning feature, and vice versa. That is, any of the closure height adjustment mechanisms disclosed herein can be used independently of any mold stack having residue cleaning features as disclosed herein. Rather, any mold stack having the cleaning features disclosed herein can be used independently of the closure height adjustment mechanism disclosed herein.

In some embodiments, the tapered female seat portion may be formed as a unitary component rather than being defined by the cavity insert 106 and the cavity flange 109 in combination.

The stop member 560 need not be a cylindrical pin with a radial flange. In other embodiments, the stop member may instead take another form, such as a rectangular bar. It should be understood that the first stop need not be a radial flange, but may be an alternative form of projection such as a bump, shoulder, step, lip or protrusion. Similarly, the second stop need not necessarily be the trailing end of the stop member, but may instead be other features such as a shoulder, step, lip or projection of the stop.

It is not necessary to use a retaining pin to retain the mould part (here the stripper plate) with which the stop member is associated.

It should be understood that in all embodiments, the stop member does not necessarily have to be retained with the stripper plate die member. In some embodiments, the stop member may alternatively be retained with an adjacent mold component, e.g., a core plate. In such embodiments, the stop member may be biased rearward relative to the core plate to a rearward limit where the head end of the stop member clears the spacer. This may be done to ensure that when the mold is opened and the stripper plate assembly is separated from the core plate assembly (i.e., when the first stop (radial flange) ceases to engage the stripper plate), the stop member will, by virtue of the rearward bias, reach a position where the head end does not interfere with the movement of the spacer from the outboard to inboard position.

The length L1 of the rear portion of the stop member will typically be greater than the thickness of the peel plate. However, in some embodiments, it is possible that the length L1 may be such that the trailing end of the stop member may be flush with or below the front of the peel plate when deployed, with a corresponding nub on the back of the cavity plate, to provide the necessary gap G2.

In the above-described embodiment of the closure height adjustment mechanism 501, as the mold closure height S' increases to effect, the engagement between the first stop member 568 of the stop member 560 and the mold section (stripper plate) 520 is a direct engagement between the back side 565 of the stop member 568 and the front side 567 of the stripper plate 520. It will be appreciated that in some embodiments, this engagement may be indirect, for example may occur through one or more intermediate components rather than directly between the first stop and the mould component.

Claims

1. A mold stack (103, 303), comprising:

two adjacent mold stack components for jointly defining at least a portion of a mold cavity (105, 305), the two adjacent mold stack components being a split mold insert (114, 314) and a cavity insert (106, 306);

a vent (150, 350) at least partially defined by one of the mold stack components, the vent adjustable between:

a molding configuration wherein the vent is configured to vent gas from the mold cavity while preventing passage of any substantial amount of melt therethrough; and

a cleaning configuration, wherein the vent is configured to receive melt from the mold cavity to clean the vent; and

the cavity insert (106, 306) defining an annular groove (135) along a portion of the conical concave seat (130), the annular groove (135) being formed between the central annular lip (133) and a peripheral wall (137) having a taper;

the split mold insert (114, 314) defines a tapered male portion (132) having a distal annular tongue (140) configured to be received within the annular groove (135);

the annular groove (135) and the distal annular tongue (140) define a tongue and groove connection arrangement at a junction (144) formed between a mating surface of an annular lip (133) of a cavity insert (106, 306) and an inwardly projecting shoulder (142) of a split mold insert (114, 314);

the joint is adjustable between:

a molding configuration in which the mating faces contact one another to define a parting line of the mold cavity; and

a cleaning configuration, wherein the mating faces are separated to create a space (146, 346) between the mating faces, the space serving as an extension of the mold cavity, and wherein the junction further defines an auxiliary melt barrier (151, 351) for preventing uncontrolled flashing from the extension, and upon separation between the mating faces, the split mold insert halves (116, 118) are arranged to freely laterally separate into dimensions suitable for flashing to occur within the vent holes (150, 350).

2. The mold stack of claim 1 wherein the auxiliary melt barrier comprises an auxiliary vent configured to vent gas from the extension of the mold cavity while preventing melt from passing through the extension of the mold cavity.

3. The mold stack of claim 2 wherein the auxiliary vent is located between a tongue (140, 340) and a groove (135, 335) of the tongue and groove connection device.

4. The mold stack of claim 2 or 3 wherein the auxiliary vent is substantially parallel to an operational axis (A) of the mold stack.

5. A method of cleaning a vent in a mold stack, the method comprising:

adjusting two mold stack components of a mold stack (103, 303), the two adjacent mold stack components being a split mold insert (114, 314) and a cavity insert (106, 306);

from:

a molding configuration in which the two mold stack components jointly define at least a portion of a mold cavity (105, 305), in which a vent (150, 350) at least partially defined by one of the mold stack components is configured to vent gas from the mold cavity while preventing passage of any substantial amount of melt therethrough, and in which two respective mating faces (133, 142, 333, 342) of the two mold stack components contact one another at a junction (144, 344) of the mold stack components to define a parting line of the mold cavity, the junction comprising a tongue and groove connection arrangement,

to:

a cleaning configuration wherein the vent is sized to receive melt, and wherein the mating faces are separated to create a space (146, 346) between the mating faces that serves as a mold cavity extension, and wherein the junction defines an auxiliary melt barrier (151, 351),

and

injecting melt into the mold cavity, the injected melt entering the vent and entering the mold cavity extension, but prevented from flashing beyond the mold cavity extension by the auxiliary melt barrier;

the tongue and groove connection means comprising an annular groove (135), the annular groove (135) being defined within a portion of the cavity insert (106, 306) along the tapered concave seat (130), the annular groove (135) being formed between the central annular lip (133) and a peripheral wall (137) having a taper;

the tongue and groove connection means further comprising a tapered male portion (132), the tapered male portion (132) having a distal annular tongue (140) configured to be received within an annular groove (135);

the joint (144) is formed between a mating surface of an annular lip (133) of the cavity insert (106, 306) and an inwardly projecting shoulder (142) of the split mold insert (114, 314);

wherein, with separation between the mating faces, the split mold insert halves (116, 118) are configured to freely laterally separate into a size suitable for flashing within the vent holes (150, 350).

6. A mold stack (303) defining a mold cavity (305) for molding a preform, the mold stack comprising:

a lock ring (311) defining a tapered female seat (370), the tapered female seat (370) having a tapered inner surface terminating at an annular surface;

a split mold insert (314) defining a molding surface of the mold cavity for molding a neck finish portion of the preform, the split mold insert having a split tapered male portion (380), the split tapered male portion (380) having a tapered outer surface terminating in an annular surface complementary to an annular surface of the lock ring, the split tapered male portion (380) configured to mate with the tapered female seat of the lock ring to align and hold closed the split mold insert, the split mold insert further defining a recess (353) extending coaxially through the split tapered male portion;

a core ring (339) defining a molding surface of the mold cavity for molding at least a portion of a top sealing surface of the preform, the core ring configured to be received within the recess defined in the split mold insert; and

a vent (350) for evacuating air from the mold cavity, the vent comprising:

a main vent hole (352); and

an auxiliary vent hole (354),

wherein the primary vent and the secondary vent are each defined between the split mold insert and the core ring.

7. The mold stack of claim 6 wherein the primary vent is defined in part by a recessed face (358) of the recess in the split mold insert.

8. The mold stack of claim 6 or claim 7 wherein the secondary vent comprises a gap between the split mold insert and the core ring, the gap being substantially parallel to an operational axis of the mold stack.

9. The mold stack of claim 6 wherein the primary vent comprises a gap between the split mold insert and the core ring, the gap being substantially orthogonal to an operational axis of the mold stack.